An On/Off valve is used to stop or allow flow. It is not useful for controlling the rate of
flow; a metering valve should be used for that purpose.

An On/Off valve is usually placed at the column outlet when doing gravity-flow chromatography. Closing a
valve at the column outlet will stop the flow and yet keep the column packing wet even if a leak were to develop.
For medium-term storage of a packed column two valves are usually used, one at the column inlet and
one at the outlet. This also helps to keep the column packing wet.

Both ends of these valves have tubing connectors. They are available for use with 1/16", 1/8" or
1/4" OD tubing. A reducing valve is also available which accepts 1/4" OD tubing on one end and
1/8" OD tubing on the other.

The only wetted material in these valves is PTFE (an inert, white fluoropolymer).

Metering valves have a needle stem to allow for a fine adjustment of the flow rate as well as
simple positive on/off control which does not affect the setting of the needle. This makes the flow
adjustment reproducible, even if the flow needs to be temporarily stopped between experiments.

These valves are available either with fittings for 1/8" OD tubing or with one 1/4" OD
fitting and one 1/8" OD fitting. The only wetted materials in these valves are PTFE and Kel-F.

The 3-Port T-Bore Valve is used for mixing, solvent selection, and flow diversion.
It has 3 tubing fittings for 1/8" OD tubing. The T-bore in the valve allows any 2 or
all 3 ports to be connected together.

The 4-Port T-Bore Valve is also used for mixing, solvent selection, and flow diversion.
It has 4 tubing fittings for 1/8" OD tubing. The valve connects each fluid port with
one of those adjacent to it.

The Stream Splitting Valve combines a 3-Port T-Bore valve with a metering valve. This valve has
3 tubing fittings for 1/8" OD tubing. The T-bore in the valve allows any 2 or all 3 ports to be connected together.
One of the tubing fittings also has a needle valve. This allows the fluid stream to be easily and reliably split between 2 of tubing fittings.